how much absorbed from the injection

[suresh786]

from tablet 1% is absorbed approximately

from injection?

[Galixie]

Technically all of it, because you're bypassing the digestive system entirely. But I think the answer you're looking for depends on your body and how much is already circulating. The research on injectable cyanocobalamin states that between 50 and 90% of the injection can be excreted from the body in the first 48 hours after the injection. So it's fair to say that at least 10% remains in the body longer than 48 hours.

[may61 in reply to Galixie]

Have just had had three blood tests done since original loading dose three months ago and I agree it is for me looking like 90% of the injection has gone so you prob right

[fbirder]

100%.

[Gambit62 Administrator]

dealing with a B12 deficiency is much more complex than just the amount in your blood. It is the amount that is available at the cell level and there isn't a good test for that, which is why monitoring symptoms is important.

B12 is used in a number of key systems in your body, including the production of red blood cells, resetting neuro transmitters so signals get through properly, maintaining the lining around nerve cells, recycling MMA and homocysteine into useful building blocks, and the ATP-ADP cycle that releases energy to cells, like those in your muscles. Symptoms of B12 deficiency may relate to one or more of these uses. Each will take a different time frame to correct. eg effects of anaemia are corrected as old red blood cells die and are replaced by new ones. red blood cells live for about 4 months so that will take 4 months to recover. Nerves regrow slowly so that can take a very long time. Other processes will be much quicker.

The rate at which you excrete B12 is higher when the levels in you blood are high, so as Galixie says could be only 10% left after 48 hours even though 100% is initially absorbed.